Control apparatus



Dec. 21, 1943. w, s LANDQN 'ETAL 2,337,476

CONTROL APPARATUS Filedflet, 29, 194os Sheets-Sheet '1 l lNVNTORS FIG-1Dec. 21, 1943. w. s. LANDON ETAL 2,337,476

CONTROL APPARATUS Filed OCt'. 29, 1940 3 Sheets-Sheet 3 FIG-5 1 RI 0rrrrr INVENTORS BYW AL. M

WK M

n5 5 2 5 6 FIG-8' Patented Dec. 21, 1943- CONTROL APPARATUS Walter S.Landon and Philip S. Russel, Detroit,

Mich., assignors to Detroit Lubricator Company, Detroit, Mich., acorporation of Michigan Application October 29, 1940, Serial No. 363,367

35 Claims. ff'his invention relates generally to control apparatus andmore particularly-to means for.

controlling the flow of fuel and air to a fluid fuel burner.

An object of this invention is to provide a new and novel method ofcontrolling the flow of fuel and air to'a fluid fuel burner.

Another object is to provide correct combustion in a hydroxilation typeburner during the step of changing the rate of combustion.

'Another object isto provide means or rereference, the numeral Idesignates the usual power line for supplying electrical energy to apower switch 2. primary coil of a step-down transformer 6 to manuallyoperable double-pole single throw Lead wires 3, 4 connect the the switch2. A lead wire I connects one side of a transformer secondary or lowvoltage coil 0 ducing the size of the oil pool in a-hydroxila -tion typeburner prior to reducing the air supply to prevent a smoky flame.

Another object is to provide an intermediate .step of operation in whichthe fuel flow is such that the burner will operate indefinitely withoutdamage with either high fire or pilot fire The invention consists in thenew and novel cooperation of and combination of parts, to be more fullydescribed hereinafter and the novelty of-which' will be particularlypointed out and distinctly claimed- In the accompanying drawings, to betaken as a part of this specification, there is fully and clearlyillustrated a preferred embodiment of the invention, in which drawings:

Figure 1 is a schematic view of the control system incorporated into anoil burningappa-' ratus; Y

Fig. 2 is a simplified schematic view-showing the wiring diagramfor thecontrol system;

Fig. 3 is a view in side elevation with certain. oi the parts brokenaway showing a control means embodying the invention;

Fig. 4 is a top plan view of the means of mrows; g

-Fig. 6 is a view substantially along the line 8-8 of Fig. 4 looking inthe direction of the arrows and with certain of the parts removed.

Fig. 7 is a partial view substantially along the of the transformer 6 toa contact member 9 of 'a room thermostat, diagrammatically shown at Ill:The thermostat comprises a current con-' ducting bimetallic blade IIwhich carries 'and' has electrically connected thereto, a currentconducting spring member 12. Upon decreasing temperature of the air orother medium surrounding the blade II to a first predeterminedtemperature, a contact member l3 carried by the free end of the springmember l2 will be moved due to movement of the blade ll toward the leftso that member I3 engages the contact member 9 to complete a medium fireelectric control circuit between the blade II and a lead wire I. Thespring member l2 flexes toward the blade II to move further toward theleft upon subsequent decrease in temperature of the surrounding mediumand the contact members! and iii will be maintained in engagement at allblade temperatures below, the first predetermined temperatureirrespective of any movement of the blade H. Subsequent to apredetermined decrease in temperature of the blade ll below the firstpredetermined temperature, a contact member l4, shown as rigid with theblade II, will engage a second stationary contact Fig. 5 is a viewsubstantially along the line 5-5 of Fig. 4 looking in the direction ofthe arline 1-1 of Fig. 4 looking in the direction of the arrows;

Fig.8 is' a view of certain of the parts showing their cooperativerelationship;

Fig. 9 is a viewin section of one feature of the invention, and

f, member I5 to close a high fire electric control circuit. It is tolbeunderstood, however, that any type of room thermostat which closes anelectrical circuit at one predetermined temperature and closes a secondelectrical circuit upon the occurrence of a predetermined lower secondtemperature may be used. It is to be noted, however, that the thermostatmust maintain the respective circuits closed at all temperatures belowthe temperature at which the circuit is closed. Preferably the contactmembers 8 and I3, and M and I5 should engage and break with a snapaction. A thermostat. similar to that shown, described and claimed by E.J. Dillman in a copending application, Serial No. 263,486, filed March22, 1939, now Patent No. 2,255,021 granted Sept. 2, 1941, and assignedto the assignee of this invention may be used. By connecting thetransformer secondary'coil 8 to the the circuit is not first madebetweencontact members 9 and I3.

The blade H is connected by a lead wire I. to one terminal of aresistance heater I I which acts upon energization to heat a bimetallicpower element I8. The other terminal of the heat- -er i1 is connected bymeans of a lead wire I! to one terminal of 'a second resistance heaterwhich acts upon energization to heat a second bimetallic power element2|. A lead wire 22 connects the other terminal of the heater 20 to ahorizontally extending movable switch arm 23, to be described more indetail hereinafter.

' which carries a contact member 24 normally held in engagement with'acontact member 26 carried-by a flexible or hinged electrical con-'ducting arm 28. The arm 26 is electrically connected by a lead wire 21to the transformer secondary coil 8 at the end opposite to thatconnected to the lead wire I. The circuit just deassmvc away from theport 8| into'an open position with I the shoulder 83' against a movablearm 1 of the bimetallic power element It. Movement of the valvemember-I2 toward valve closed position by theelement I8 is limited byengagement of the arm 51 with a lower flange portion of a low flre stopmember 58. The member 58 is preferably screw-threaded. into a rigidplate member 5! which has a fixed position relative to the wall It andport bl.

The element It is rigidly secured by means of a bracket 80 to a'rigidplate or wall member scribed constitutes the medium fire controlcircuit.

The contact member I! ispconnected by means 35, has a rotor 38 and awound stator 31. The

motor is preferably so constructed that it may assume a plurality oflongitudinal positions to 'be described in more detail hereinafter.

One terminal of the wound stator 31 is connected by means of a lead wire38 to the lead wire 3 and the other terminal of stator 31 is connectedby means of a lead wire '39 to a movable blade 40 of a diagrammaticallyshown single pole doublethrow switch 4|. The blade 40' carries upper andlower contact members '42, 43 which are positioned substantially inalignment one on either of lead wire 28 to one terminal of a resistanceheater 2! which acts upon 'energization to heat 6i and the element 30 isrigidly secured by means of a bracket 62 to a rigid plate or wall member63. When the element 30 is deenergized, an arm 64 thereof engages alower flange of a medium,

fire stop member 65 threadedly secured to the plate member 59. Upwardmovement of the valve member 52 is limited by engagement of the shoulder53* with the arm 84'for medium flre position. A high flre stop member 88is also threadedly secured to the plate member I. and

its lower end portion is engageable with the upper end 01 the-valvemember stem portion 83 to limit maximum or high fire opening movement ofthe valve member 52.

A reciprocally movable thrust member 81 is guided for vertical orlongitudinal movement within apertures throughthe wall 54 and the platemember BI and has a shoulder 0| adjacent its upper end portion which is"engageable with,

the bottom surface of the lower flange portion of the stop member 58 tolimit its movement in an upward direction under the influence of aclosed position, the shoulder 10 can never engage side of the blade 40.In the position shown' the contact member 43 is in engagement with acontact member 44 carried by a hinged or flexible current conducting arm45. The arm 45 ig'connected by a lead wire' 46 to. an auto secondarytap" on the primary .coil 5 so that reduced voltage is supplied to themotor 35. The

contact member 42 is operable under certain conditions of operation toengage a contact member 41 carried by acurrentconducting resilient orhinged member 48.- A lead wire 48 connects the member 48 to the leadwire 4 so that when contact members 42, 41 are in engagement and members43, 44 are parted, full line voltage is placed on the stator 31. v

The numeral 50 indicates the bottom wall of l a liquid fuel chamberwhich has an outlet port 5! controlled by means of a reciprocallymovable valve member I2 having a stem portion 53 which extends upthrough and is guided within an aperture in-a rigid wall 54. The portion53 has a shoulder II adjacent its upper end and a flange I! which ispositioned intermediate its shoulder 53'- and the wall I4. A helicalcoil compression spring I! is positioned concentric with the stemportion II intermediate the wall 54 and flange 5i and acts to urge thevalve member I2 upward leaf spring 69 and which action will be describedmore in detail hereinafter. The maximum downward movement of the thrustmember 81 is limited by engagement of a lower shoulder Ill thereof withwall 54 but the shoulder 10 is preferably so positioned that within thedesired range of adiustment'of the low flre stop member l! the arm 51will be limited in its clockwise movement. by engagement with the stopmember ll prior toefigagement of the lower shoulder II with the wall 54.iustable range of the member it include full the wall 54 as long as thevalve member 52 is in position. The thrust member 61 is continuallyurged in an upward direction by a-component of force exerted by the leafspring 89. which is transmitted-to-the member 81 through a thrust pin IIhavingcne of its conically shaped end portions in substantial pointcontact with the spring 69 and having the other of its conically Yshaped and portions in substantial point contact with a downwardlyextending leg I2 of the movable blade 40. Because the point ofengagement of the pin "Ii with the leg "I2 never passes below animaginary line drawn between the pivot point of blade 40 and the pointof engagement of the pin II with the spring 89, the blade 40 .iscontinuallyurged by the spring 89 into engagement with the bottom end ofthe thrust member 81.

As is well known those skilled in the art, when a bimetallic powerelement 'is heated or cooled the actuating portion thereof will tend tomove in accordance with temperature change. The force exerted by the arm51 of element It will be dependent upon the temperature of the element I8 and the position of the arm 51. 111.

no external forces were applied to the arm 81 to prevent its freemovement, for any given temperature of the element It, the arm 51 wouldhave n it is desired that the adi a definite position, but due to theexternal forces of the springs 56 and 69 the arm will not take-adefinite position with a given temperature of the element 18, i. e. thespring forces change with the spring movement and may build up ordiminish disproportionately to temperature change acting on element [8.The bimetallic power element l6 being made of metal will have a definitemodulus of elasticity and therefore a position assumed by the arm 51under the influence of the springs 56 and 69 will cause an elastic orresilient force to be exertedby the element 18. The free position of thearm 51 is so chosen that when the element I8 is at room temperature, thearm 51 will be held in a displaced upward position resting upon the heador flange of the stop member 58 and will be exerting a downward forcegreater than the sum of the upward forces exerted by the springs 56 and69. By this arrangement, the valve member 52 will be held in pilot fireposition determined by the head or flange of stop 58 and the switch 4!will be held with the contact members 43, 44 in engagement during theperiods when the element I8 is at room temperature. Thus, if the forceexerted by the arm 51 in holding the members 52 and'61 in the positionshown in Fig. 1 be decreased, there comes 3 a time when the forceexerted by arm 51 just equals the upward force exerted by springs 56 and69. Upon a further decrease'in force exerted by arm 51,-the springs 56and 69 will cause the arm 51' to rotate in a counterclockwise direction.If the'force exerted by the springs 56 and 69 remained constant duringupward movement of arm '51, the arm 51 would assume a given position forevery given temperature but in the instant arrangement the sum of theupward forces exerted by the springs 56 and- 69 will vary depending uponthe position of the members 52 and 61 so that the elastic or resilientforce exerted by the arm 51 will vary. The spring 69 is so arranged andpositioned relative to thrust member 61 that the force component.-clockwise movement out of its temperature determined 'position'and ofthe decrease in force exerted by the spring 56- due to its increaseinlength as it moves the valve member 52 upward to maintain its engagingrelation with'the arm 51. By proportioning or relating the forces asabove set forth, it is possible for the parts and particularly the valvemember 52 to be moved with a quick or snap acting movement from theposition shown in Fig. 1 into an intermediate position or to ahesitatiorr point in which the shoulder 68 is in engagement with thelower flange of the low fire stop member 58 at which position the upwardcomponent of force exerted by the spring 59 is absorbed by the stopmember 58 and is ineffective to influence or to aid in the movement ofthe element iii in a further upward direction. During this initial stageof upward movement which is prior to engagement of shoulder 68 withstopmember 58, the downward force exerted by the arm 51 was somewhatless than the total of the upward forces exerted by the springs 56 and69 but considerably more than the upward force exerted by the spring 56when acting alone. Therefore uponshoulder 68 engaging stop mem ber 58and before any subsequent upward or opening movement of the valve member62 can occur, the downward force exerted by the arm 51 must besubstantially reduced to compensate for the loss of the. upward forceexerted by the spring 69. Thisdownward force of arm 51 is proportionalto the temperature of the element 18 and, since it takes the heater G1 aperiod of time to increase the temperature of the element l6 and reduceits force to a pressure less than that of spring 56, the valve member 52will be held in this intermediate position by the element arm 51 untilsuch increase in temperature of the element l8 occurs. Further increasein temperature of the element 18 beyondthat at which it-balances orequals the force of spring 56 will cause arm 51 to gradually movecounterclockwise until the shoulder 53 engages arm 64 at .which timefurther upward movement of the valve member 52 is prevented and anyfurther counter-clockwise movement of the arm- 51 will merely move thearm 51 away from the valve membenand will not allow the valve member 52to move any further toward open position. It may thus be seen that uponopening movement of the valve member 52, it is initially moved with arapid movement into a flow positionintermediate the low fire position(the position shown in Fig. l) and medium fire position and then after apredetermined time interval gradually moved from the intermediateposition to the medium fire position. The thrust member 61 will moveduring the rapid initial movement of the valve member 52 with a quickmovement into engagement with the stop member 58 to cause the contactmembers 43, 44 to part with a quick action and the contact members 42,41 to engage to s pp y the Stator 31 of motor 35 with full line fixedrelation with the stator 31 and the other end of the spring 11 acts tourge the shaft 16 and the rotor 36 toward the left (see Fig. 1) so thatthe rotor 36 is held in a displaced position relative to'the stator 31at the reduced stator voltage provided when switch 4| is in the positionshown. When full line voltage is applied ,to the stator, i. e., when theswitch 4| is in its other po-- sition, the solenoidal force of: thestator 31 will pull the rotor 36 toward alignment with the stator 31against the force of spring 11 and the speed of rotation of the rotor 36will also be increased. The shaft 15 extends from the rotor 36 throughan aperture in a damper 19 and is shown as having a. flange or headportion 86 which is engageable with the damper 19 upon movement of therotor 36 toward alignment'with the stator 31 to rotate the damper 19about its fulcrum 8! until a lower edge 82 of the damper 19 engages anarm 83 of the power element 33. The cold or deenergized position of thearm 83 is regulated by engagement with the upper surface of a flangeportion of a stop member 84 which is threadedly secured to a wall member85 which is in a fixed position relative to the fulcrum 8L. The arm 83acts upon engagement of theedge 82 to limit its- 4. movement to theposition-at which the correct air will be supplied for the fuel admittedby the valve member 82 at medium iire position with the shoulder 88against arm 8| and with the element 80 deenerglzed or at roomtemperature.

The damper I is so arranged relative to its fulerum point that the areaof the damper 18 below the fulcrum 8| is greater than the area above thefulcrum 8| so that the suction caused by the I fan will tend to rotatethe damper u to the position shown in full line (see Fig. 1). Should thefan I! stop due; as for example, to aburnedout motor the suction eifectof the fan "will cease and due to the balance of the damper ll it willswing to the dotted line position (see Fig. '1). It will be noticed thatthe upper portion of the damper I0 is bent inwardly. This accompllshes atwo-fold purpose of balancing the damper for movement into the dottedline position and also of allowing sufllcient air to bypass the damper"for forced draft low or pilot deenergized positions and the valvemember 82 and the fan I8 will therefore be set for low fire operation.Once the lever 02 has moved to tripped position it will remain in thatposition until the reset member 08 'is pushed downward to allow the arm0| to slide into the position shown (see Fig, l) with its end inengagement with the leg .02..

fuel is supplied from a suitable source of sup- -are operation when thefan is operating as shown. 1 The element 22 has a definite operatingcharacteristlc relative to the element 80 so that upon energization ofthe resistance heaters and 82, which are in series circuit, the arm 82will be moved against a stop member 80 prior to movement of the arm 84to allow movement of the 'valve member 82 to high fire position. One wayin which this may be accomplished by using sim-' ilar elements andheaters is by so arranging the element 22 that when it is at roomtemperature or deenergized, the arm 88 engages the stop member 84 verylightly and by choosing the element 80 so that when it is at roomtemperature or dewith a much'greater force. In this way a rela- *tivelysmall increase in the temperature of the element 83 will cause the arm88 to move against stop member 88 while .a much greatertemperatureincrease of element 20 will be required to move the arm 84 away from thestop member 65,-

ply (not shown) through an inlet I08 leading into a strainer chamber I0lwhich may be in-' tegral, withthe bottom wall I04. From the chamber I01,the strained liquid fuel flows into the chamber I08 through any of theusual valve members actuated by suitable means and well known to theprior art so that a substantially constant liquid fuel level ismaintained in the energized the arm 84 engages the stop member 88 Ychamber I05 at the lever L-L. Extending upwardly from the wall I04 intothe chamber Ill is a boss I08 which has two longitudinally extendingpassageways I08, III which open together at their intersection below theline Ir-L and open downwardly through the wall I04 into a hollow outletIII which may be internally threaded for'receiving a conduit from a fuelburner (not shown). The passageway I00. extends upwardly. through theboss I08 and opens through the top wall thereof above the line 'L-L. Thepassageway H0 also extends 'up- Other-means could be employed such asusing heatings'elements with different heating effects or by insulation.4 The element v2I is positioned so that it'is cooled in some mannerby'the air stream from the fan 'll and as shown the element 2| issupported by means of a' support 81 within an outlet duct 88 whichtransmits the air from the fan I! to a burner 88. diagrammaticallyshown. The bumer 88 issupplied with fuel by means of a conduit 00 whichleads from the outlet port ii to the burner 88. Should the airoutputfrom the fan I! fail or fall below a predetermined minimum for anyreason, the element 2| will be heated by the resistance heater-20 sothat the arm 8| will move downwardly beyond the end of a downwardlyextending'leglz of a bell-crank lever 98 fulcrumed as at 84. The switcharm 28 forms the other leg of the lever 88. Aspring or other urgingmeans 88, which is shown as being positioned intermediate the top wall08 of the duct 88 and the horizontally extending switch arm 22, acts topivot the lever 08 in a counter-clock wise direction to part the contactmembers 24 and 28 upon movement of the arm 8| beyond the end of leg 82.Counter-clockwise movement of the lever 03 is limited by engagement ofthe arm 23 and a head portion 88 of a manually reset member 80 andengagement of the head portion 88 with a rigidly positloned wall member88-. Opening 'of the contact members 24, 28 acts to deenergire theresistance heaters. ll, 20, 28 and 32 so that the elements II, 2|, 30and 83 will return to their wardly through the'boss I08 and opensthrough the top wall thereof but the passageway H0 is communicativelyconnected to the chamber I00 v for liquid fuel flow from a point belowthe line L L throughout the remaining upper portion of the passagewayIIO by means of a longitudinal slot III extending through the wall ofthe boss I08 intothe passageway H0. The passageway, IIO has threedifferent internal diameters from its lower to its upper end and aplurality of shoulders H2, H8 are formed at the intersection of thedifferent diameters. Press-fitted within the passageway -I I0 andseating against the shoulder II2 is'a tubular seat member Ill having anorifice IIS and a seating surface 8. Liquid fuel from the chamber I08flows through the slot Hi9 and through the seat I member Ill into thepassageway IIO to flow.

through-the outlet III to the fuel burner (not shown). The rate ofliquid fueLflow is cone trolled by means of a valve member II! which hasa reduced diameter portion I18 and a conic portion -H8 connecting thereduced portion III with the normal diameter portiom The" valve memberI. I! has a longitudinal central passageway H8 extending therethroughwhich has its upper end portion opening radially outward into thechamber I05 above the lever L-L and has its lower end opening throughthe lower end portion of' the member I I1 into the seat member III belowthe orifice I I 5. .The reduced portion H8 is reciprocally slidablewithin the oriflce'l II in piston-tight relationship and has a V-shapedslot I20 which adlustably r isters with the oriflce H for controllingflow of liquid fuel from the chamber I 05. Fuel is prevented fromflowing position, the conic portion I I9 engages the seat member II4 tocompletely stop the flow of fuel from the chamber I05. The passagewaysI09 and H9 act to maintain atmospheric pressure or the same pressurewhich exists above the fuel in chamber I05 within the. outlet III sothat the only force acting to promote flow of fuel from the chamber I05is the liquid fuel head itself.

The valve member II1 has a stem portion I2I which extends upwardlythrough the chamber I05, through an aperture in a bottom wel I22 of theupper casing IIJI. A split ring I23 is rigidly secured to the stemportion I2I within the chamber I05 and serves as one abutment for an endmember I23 which is concentric with and loosely fits .the portion I2 I.A helical coil spring member I24 is concentric with the stem portion I2Iand is under compression between the shoulder |I3 and the member I23 andurges the member I23 against the ring I23. The spring member I24normally acts to urge the valve member H1 in an upward direction awayfrom the orifice H5 and surface I I6. The aperture through the wall I22is preferably of suitable size so that the valve member II 1 and itsattached ring I23 may be removed upward therethrough. Upon removal ofthe member N1 the member I23 engages the under sur-' face of the wallI22 to hold the spring I24 from.

passing through the aperture.

The casing IIII has a front side wall I25 which extendsupward from thebottom wall I22 approximately one third of the distance to the open topwall I26 of the casing I0 I and has a plurality of rear walls I21, I26which extend upwardly from the wall I22 and are joined at one endportion to end walls I29, I30, respectively, of the casing NH. The wallsI21, I26 each extend f toward each other and the walls I21, I28 eachterminate approximately one third of the distance from the respectiveend walls I29, I30 to which it is joined to the respective opposite endwalls I30, I 26. A U-shaped wall member has the open end of its parallelside walls I3I, I32, respectively, secured to the facing end'portions ofthe walls I21, I28, respectively, and has its connecting .or rear wallI33 extending Vertically vided into a transformer compartment I42, ahigh voltage terminal compartment I43, a low voltage compartment I44,and a switch compartment I45.

A transformer I46 is held, as by screws I46, to the wall I33 and has lowvoltage lead wires I41, I46 leading to the low voltage terminal stripI31 and high voltage lead wires I43, I50, I5! leading to the highvoltage terminal strip I36. Toe lead wires I50, I 5I are connected tothe end points of the transformer primary coil while the lead wire I49is connected to the primary coil at an intermediate point thereby makingthe primary coil serve the dual purpose of its usual function and alsoserving as an auto-transformer. The high voltage terminal strip I36comprises a strip of insulating material in which are secured fourterminals I52, I53, I54 and I55. The lead wires I49, I50 and I 5i areconnected respectively to the terminals I52, I53 and I54. Electricallyconnected to the terminal I55 and secured to the insulating materialstrip is one end of a resilient switch blade member I 56 having'a bladeportion I56 extending longitudinally of and normally urged toward theinsulating strip which carries oppositely facing contact members I51,I58. The contact members I51, I58 cooperate respectively with stationarycontact members I59, I60 positioned respectively above and below thelongitudinally extending portion of the blade member I56 to form a singlpole double-throw switch. The contact member I60 is electricallyconnected to the terminal I52 and the contact member" I59 iselectrically connected to the terminal I53. Main lead wires (not shown)conduct electrical energy from a suitable. source of supply (not shown)and are connected to the terminals I 53 and I54. Leadwires I59 and I59connect the to and upwardly from the wall I22 substantial- 1y along itslongitudinal centerline. An L-shaped member, to be described more indetail hereinafter, is secured with its horizontal bottom or baseportion I34 in engagement with the top portion flush with its outerface. The portion I38 extends substantially parallel with the bottomwall I22 and has the opposite side edge portion abutting the wall I33. Avertical end portion or wall I35 of the L-shaped member has its frontedge portion flush with the outer face of the wall I25 and its rear edgeportion engaging the wall I3I with the outer face thereof, substantiallyflush with the outer face of the wall I3I. High voltage and low voltageterminal strips I36, I31,.respectively, extend parallel with now be seenthat the upper casing II is diedge of the side wall I25 and with oneside edge terminals I54, I55 to the controlled electrical apparatusi60diagrammatically shown in Fig. 10, and which may be a blower fantosupply the necessary air for combustion of the liquid fuel dischargedfromgthe chamber I 05.

The low voltage terminal strip I31, like the strip I36, comprises asubstantially rectangular plate-like member I 6| which may be "Bakeliteor other suitable insulating material. The strip I6I has its endssubstantially registering with and resting on the upper edge of thewalls I25, I28 with one side edge conforming with and positioned againstthe end wall I30. The other side edge I62 of the member I6I fits snugly=against the wall I32 and has a. portion I63 which extends the terminalsI61, I68, respectively. A bus bar I12 has one end secured to theterminal I66 and extends along the top face I65 beyond the end ofthewall I32 adjacent the portion I63 where a finger portion I13 is bentdownward beyond the edge portion I63 toward the bottom wall I22. Asecond bus bar I15 is secured to the terminal I12 and extends therefromalong the topface I 65 toward the edge portion I63 where a fingerportion I16 is bent downward beyond the portion I63 intermediate thefinger portion I13 and the wall I25. A third bus bar I11 is secured tothe terminal I13 and extends therefrom along the top face I65 toward theedge portion I63 where a finger portion I18 is bent downward beyondtheedge portion I 83 intermediate the 'finger portions I13 and I16.

A medium fire power element I18 and a high the power element I80 havetheir supporting members I8I, I82, respectively, secured to the uppersurface of the L-shaped member portion I 34. The power elements I18, I80preferably are similar to those in the copending application of WalterS. Landon, Serial No. 339,427, filed June 8,

1940, and comprise cylindrical portions I83, I84, actuating or movableportions I85, I86 and re- 'sistance heaters I81, I88, respectively. Themovable portions I85, I86 have V edges which overlie and engage anupwardly facing shoulder I88 of the valve member stem portion I2I whichextends upward through an aperture in the portion I34, Normally, whenthe power elements I18, I80 are deenergized, the movable portions I85,I86 are urged in a downward direction to move the valve member II1toward closed position. Movement of the portion I86 in. a downwarddirection is limited by engagement thereof with a flange I80 of a stopmember I 8| screwthreade'd to a plate member I82. The member I82 ispositioned substantially parallel to and spaced above the portion I34and is held in place by a plurality of screws I83 against the top endsof a plurality of cylindrical members or bosses I84 which may be castintegral with and which extend upwardly from the portion I34. To addstrength to the bosses I84 and for convenience in casting they may bejoined together by webs I85.

A tab I86 extends downwardly from the lower face of the portion I34 andhas an aperture for receiving one end of a fulcrum pin I81. A second tabI 86, which may be in the form of a longitudinal reinforcing ribextending downwardly from the lower face of the portion I34, is spacedfrom the tab I96 and has an aperture aligned with the aperture in tabI86 for receiving the other end of the pin I81 about which is fulcrumeda bifurcated end I88 of a lever member I98. The member L88 extendsalong,'beneath and adjacent, the lower surface of the portion I34 andterminates in adownturned portion 20I which has an indentation 202, thepurpose of which will be hereinafter described. Secured to the levermember I88, adjacent the portion 20I, is an insulating strip 203 whichextends beyond the end of the lever member to engage the upper surfaceof the blade member I56 so that the lever member I88,is operable uponcounter-clockwise rotation (see Fig. 6) to move the switch blade memberI56 downward to cause the contact members I51, I58 to break circuit andthe contact members I 58, I60 to make circuit. Secured to the wall I35and extending downward therefrom toward the bottom wall I22 is a leafspring 204 which has at its lower end portion an indentation 205 spacedtoward the wall I28 from the indentation 202. The indentation 205 ispositioned so that when the lever member I89 is above an imaginary linedrawn between the indentation 205 and the fulcrum pin I91. .A thrustmember '206 has its opposite end portions pointed and preventunauthorized tampering by inexperienced persons.

and guided in the aperture 208 and the lower 'spective circuits.

surface of the portion 2I2 engages the raised portion 201 so that as thethrust member 208 is reciprocated between the fixed limits as determinedby the shoulders 2I0 the lever member is rocked to cause the blademember I56 and contact members I51, I58 to make and break their re- Acollar member 2I3 is adjustably screw-threaded to the thrust member 209intermediate the plate member I92 and base portion I34 and has ashoulder portion 2 against which the V edge of the movable portion I85engages. The upper end of the thrust member 209 has a screw-driver slot2I5 so that the thrust member may be rotated thereby to move the collarmember 2I3 longitudinally thereof. The collar member 2I3 is held againstrotation with the thrust member 208 due to engagement of a flat sidewall surface portion 2 I 5*- which upon attempted rotation thereofengages the side edge portion of the movable portion I85. In this mannerthe maximum downward movement of the actuating portion I85 is determinedand also the minimum fuel controlling position of the valve member '1. Ahelical coil spring 2I6 is positioned concentric with the thrust member208 with its end portions engaging the flange portion 2I2 and the lowerend surface of the collar member 2I3 to prevent unwanted rotation of thethrust member 208 during operation of the control means. The extremeupward or opening movement of the valve member I I 1 is limited byengagement of the top end of the stem portion I2 I with a high fireadjustment screw 2I1 which is screw-threadedly secured to the platemember I 82 in alignment with the longitudinal axis of the valve memberstem portion I2I. Unwanted rotation of the screws 2I1 and stop memberI8I are prevented by nuts 2I8 which are threaded to the screw 2 I1 andmember I 8I respectively below the member I92 and hold spring diskmembers 2 I 9, which may be members similar to lock washers, understress against the lower surface of the member I92. A locking member 220is held, as by a screw 22I, to the plate member I82 and has a bifurcatedportion engaging the nuts 2! -to hold them against rotation with themember I8I and the screw 2 I 1 during manual rotation thereof for mediumand high fire adjustment.

The heaters I81, I88 have lead wires 222, 223, and 224, 225,respectively, which extend downward through apertures in the baseportion I34 of the L-shaped member and are connected to suitableterminals 226, 221 and 228 carried on the lower face and adjacent oneedge 228 of a rectangular block 230. 'The block 230 is preferablymoulded from Bakelite" with a central recess 23I opening through an endedge 232 opposite to edge 229 so that the block 230 will fit over thelever member I89 and block 230 may be secured, as by screws 233, to thelower face of the base portion I 34. Lead wires 222 and 224 are gage.

connected to the terminal 226 while lead wire 223 is connected toterminal 221 and lead wire 225 is connected to terminal 228. Eachterminal 226, 221 and 228 has respectively secured thereto one end ofcontact strip members 234, 235 and 236, respectively. The members 234,235 and 236 extend beyond and are bent upward along and spaced from theedge 229 and have their upwardly extending end portions rounded and bentinwardly against the edge 229 so that the strip members may rock abouttheir rounded edges thereby to align themselves for good contactrelationship respectively with the finger portions I13, I16 and I18 withwhich they cooperate in a manner which may best be seen by reference toFigs. 8 and 9. Due to manufacturing tolerances and errors when the baseportion I34'is placed in position the strip members 234, 235 and 236'may not be in exact parallel relation with the finger portions I13, I16and I18 respectively so that a good electrical connection will not bemade therebetween. The finger portions I13, I 16 and I18 are thereforeso arranged relative to the strip members 234, 235 and 236 that theyengage prior to movement of the base portion I34 into its properposition with apertures 231 and 238 in the base portion I34 in alignmentwith screw holes 239 and 240, respectively, in upwardly extending bossesfrom the wall I 22. Therefore as the flat-headed screws MI, 242 arescrewed downward into the holes 239 and 240 from the position shown inFig. 9 the tapered screw head portions will cam in the similarly taperedportions of the aperture 231 or 238 to slide the base portion I34 to theright (Fig. 8).thereby causing the strip members 234, 235 and 236 torock on their rounded ends until the engaging portions align themselveswith the respective finger portions I13, I16 and I-18.

Fig. 10, which shows adiagrammatic showing of the apparatus connected toan oil burner system, like parts have been designated by like numerals.A room thermostat, diagrammatically shown at 250, has a medium firecontact member 25I and a high fire contact member 252 which areconnected respectively by lead wires 253, 254 to terminals I68 and I16.An electric conducting temperature sensitive element 255 is connected bya lead wire 256 to the terminal I69 and has se-- cured thereto a leafspring 251 which carries a contact member 258 which is operable at apredetermined temperature of the element 255 to be moved thereby intocontact relationship with the contact member 25| to complete anelectrical cir.

cuit. A contact member 259 is carried directly &

by and is operable to be moved by the element 255 into contactrelationship with the contact mernher 252 to complete an electricalcircuit upon a a predetermined temperature of the element 255 below thatat which the members 25I and 258 en- An electrically operated aircontrolling means, diagrammatically shown at 266, has one terminalconnected by a lead wire 26I to the ter minal I12 and its other terminalconnected by a lead wire 262 to the terminal I16. A bimetallic operatedelectric switch 263 has one terminal connected by a lead wire 264 to theterminal I66 and its other terminal connected by a lead wire 265 to theterminal I61. An electrical heater 266 is positioned relative to theswitch 263 so that when the air supplied to the burner by anelectrically operated fan means I60 is reduced below a predetermineddesired quantity, it is operabli to heat the switch 263 and cause it toopen thv circuit between the lead wires 264 and 265 therc.

by to deenergize the secondary circuit of th-.. transformer I46. Oneterminal of the heater 26s is connected by a lead wire 268 to theterminal I69 and the other terminal of the heater 266 is connected by alead wire 269 to the terminal "I. If desired a safety control,indicateddiagrammatically at 210, may be used to deenergize thesecondary circuit of the transformer I46 upon a dangerous operatingcondition such as excessive temperature of the medium heated by theburner.

The operation of the apparatus shown in Figs. 1 and 2 is as follows:Electricalenergy flows from the source of supply through the power lineto the switch 2. From the switch 2 it flows through lead wire 3 throughthe transformer primary 5 and lead wire 4 back to the switch 2 and tothe source of supply through the power line I. The stator 31 of the fanmotor 35 is supplied with reduced voltage through the switch M from theauto-tap 46 and the fan 15 is rotated at reduced speed. The spring 11 isacting on the motor shaft 16 to urge the rotor 36 toward the left (seeFig. 1) against the solenoidal force of the stator 31. Movement of therotor 36 to the position shown allows the damper 19 to be pulled towardclosed position due to the suction of the fan acting on its larger lowerarea. The clearance about the upper end of the damper 19 is sufiicientto allow only sufficient air to be drawn in by the fan 15 when operatingat reduced speed, to burn the pilot fire fuel which is being admitted tothe burner 89 by the valve member 52. The dotted line position of thedamper 19 indicates its position when the fan 15 is not operating andonly natural draft is supplying air to the burner 89. This is anemergency condition which will occur only in the event of a powerfailure or in some failure of the fan 15 or motor 35.

Upon a reduction of the temperature of the blade II contact member I3will engage the contact member 9 to energize the medium fire circuit asfollows: current flow from the secondary coil 8 through lead wire 1,contact members 9 and I3, member I2, blade II, lead wire I6, heater I1,lead wire I9, heater 26, lead wire 22, contact members 24, 25 and leadwire 21 to the secondary coil 8. The heater I1, being energized, heatsthe element I8 which acts to reduce the, downward force exerted by thearm 51. At a predetermined reduced downward force of the arm 51, it ismoved upward by the spring 69 acting through the thrust pin H and thespring 56 acting through the members 52 and 61. Upward movement whichoccurs with a quick action due to the increasnig upward component offorce exerted by the spring 69 is limited by engagement of shoulder 68with the stop member 58. At the same time the valve member 52 and member61 are moved upward the switch M is caused to break the circuit throughcontact members 43, 44 to cause the contact members 42, 41 to engage andsupply full line voltage to the stator 31. At full line voltage, thestator 31 exerts suificient pull on therotor 36 to urge it against theforce of the spring 11 more nearly into alignment with the stator 31.Movement of the rotor 36 toward alignment with the stator 31 causes theportion 86 to rock the damper 19 until the edge 82 engages the arm 83 atwhich time further longitudinal or axial movement of the rotor 36 isprevented. Increased air for medium fire operation is now being suppliedwhile the fuel flow is increased only to an intermediate flow which isdetermined by the distance the member 61 can the downward force exertedby the arm 51 to be gradually reduced and the valve member 52 to movegraduallly toward medium fire position" and which position is determinedby engagement of The position ofw arm 64 is determined bythe stop member65.

the shoulder 53* with the'arm 64.

Should the increased air supply fail, the heater 20 will act to heat theelement 2| and the arm'tl will move downward beyond the end of the leg92 so that the spring 95 will act to rotate the bell crank lever 93 andpart the contact members 24 and 25 thereby deenergizing any and all of 1electrical circuits supplied by the secondary coil l and sendin theburner to pilot fire operation.

Should the temperature of the blade II decrease to a predetermined lowertemperature, the contact members I4 and I5 will engage and energize .thehigh fire control circuit as follows: Current flows from the secondarycoil 8 through lead wire 1, contact members 9 and I3, member I2, bladeII, contact members I4 and I5, lead wire 28, heater 29, lead wire 3|,heater 32,- lead -wire 34, contact members 24 and 25 and lead wire 21back to the secondary coil 8. Energ'lzation of the heater 32 causes itto heat the element 33 and gradually move the arm 83 into engagementwith the stop member 86 thereby to allow the rotor 36 to move furtherinto alignment with the stator 31 and the damper 19 into high fire aircontrolling position with the edge 82 in engagement with the arm 83.Energization of the heater 29 causes it to heat the, element 30 andgradually reduce the downward force of the arm 64 so that the spring 56will gradually move the valvemember 52 upward into high fire fuel fiowposition in engagement with the stop member 66. The e1ement'33, as washereinbefore de-.

scribed, will act to increase the air flow to high fire air flow morerapidly than the element 36 increases the fuel flow so that excess airwill be supplied during .the period of increasing fuel fiow.-. Shouldthe air supply be reduced for some ments 30 and 33 will cool andgradually return' to the positions shownin Fig; 1 and move the damper=19and the valve member 62 to the me-' dium fire controlling position. Itis to be remembered; however, that movement of the valve member 52toward medium fire position will be sooner than movement of the damper19 to me-- dium air controlling position, as was set, forthhereinbefore, so that excess air is supplied during this period oftransitory operation. Upon breaking of the medium fire circuit theheater 28 p and element 2| begin'to coolwith'no beneficial result beingproduced and the heater I1 and the element It begin to cool. Cooling ofthe element I8 causes an increased downward force to beexerted by thearm 51 which Twillgradually move the valve 'member'52 5 toward closedposition and the shoulder 53 away from the arm 64. This movement occursgradually until the arm 51 engages the thrust member 61 at which timefurtherdownward movement of the arm 51 and the valve member 52 ceasesuntil the ele-' assayemember 52 and switch member 4| to the pilot fireposition with a snap action as was hereinbefore described. Thepredetermined lower temperature is so chosen relative to the temperature5 at which the arm 51 engages the member 61 that the time necessary forthe element to cool is more than a sufiicient time for the fuel pool inthe burner 89 and/or the excess oil in the conduit 90 to be burned sothat fuel is being burned in the burner at the intermediate rate whichis determined by the intermediate position of the valve member 52. withthe medium fire air supply. In this manner the burner is prevented fromsmoking due to the presence of too much fuel for the amount of suppliedair and as the intermediate fuel supply is so chosen that a suflicientquantity of fuel is being supplied to the burner to prevent the excessafnfrom drawing the flame down into the bottom of the burner pot adamaging burner condition is prevented.- It has also been found thatsuch an intermediate fuel flow will burn without smoking with pilot fireair supply and therefore when the switch 4| is moved with a quick actionto supply reduced voltage to the stator 31 and the valve member 52 ismoved with a quick movement to pilot fire fuel supplying position anon-damaging large pilot flame occurs which gradually reduces itself tothe small pilot flame which burns after equilibrium condi- 80 tions havebeen reached.

, The operation of the device shown in Figs. 3 to 10 is as follows: Inthe position shown in Fig. 10, the burner system is operating at pilotfire and the element|19is at room temperature with its movable por tionI85 urging the valve member I I1 to minimum pilot fire flow position,this minimum flow position being determined by the engagement of themovable portion I85 with the collar member shoulder portion 2| Land ofthe M) upper spaced shoulders 2"! with the top surface of the platemember I92; The thrust member 209 in this position is engaging therounded raised portion 201 and holding the lever member I99 in itscounter-clockwise position so that the strip 203 is holding the blademember I56 in its down I position and contact members I58 and I60 are inengaging relation. The fan means I6Ii is in this position of the blademember I56 being supplied with reduced voltage from the transformer I46for reduced speed operation.

As the temperature of the space being heated by the burner decreases intemperature, the element 2550f thermostat 250, which is positioned inthe heated space, will move toward the right (see Fig. 10) and at apredetermined temperature the contact member 258 will engage the mediumfire contact member 25| to energize the medium fire control circuit;Current nowfiows from the secondary coil of the transformer I46 throughlead 'wire I48 to theterminal I68. From terminal I68 the current flowsthrough lead wire 253, contact members 25|, 258, spring 251, element255, and

bar. I11, lead wire 223, heater I81, lead wire 222,

bus bar I12, terminal I61, lead wire 264, switch 263, lead wire 265,terminal I61 and through lead wire I41 back to thesecondary of thetransformer I46. Energization of this medium fire circuit acts to causethe heater I81 to heatthe portion I83 of the element l19 with a.consequent movement of the movableiportion I85 upward with a snap actionfar.'enough to allow the thrust member 209 move upwardly until the lowershoulder 2I|I engages the under face of the plate member I92 and toallow the valve member I" to move up- Y ward or toward valve openposition the same distance between the upper and lower shoulders 2I0.

The snap movement is due to the relationship 5 of the inherent tendencyof the resilient blade I56 to move upward, the changing component offorce exerted by the spring 204 through the thrust member 206, and theforce exerted by the spring I24. The springs I24 and 204 and theresiliency of the blade I56 and element I19 are so chosen that theincrease in the component of force exerted by the spring 204, actingthrough the thrust member 206, the lever member I99 and the member 209to move movable portion I85 in an up" direction (see Fig. 6) increasesupon movement of the lever member I99 in the clockwise direction morerapidly than the arithmetic sum of the decrease in forces exerted by thespring I24, resillent blade member I56 andthe increase in force due tothe resiliency of the element I19 when the parts move from the positionshown in the draw-. lugs to the position just described and which isdesignated as the transitory or hesitation position. Engagement of thelower shoulder 2 I0 with the bottom surface of the plate member I92 ab-,sorbs any extra upward force exerted by the thrust member 209 and. anyfurther opening or upward movement of the valve member H1 is dependentupon the upward force exerted by the spring I 24 and the downward forceexerted by the element I19 and therefore there is a time lapse while theheater I81 heats the cylindrical portion I83 to a predetermined highertemperature before the valve member will continue to move upward tomedium fire position which is the position in which the shoulder I89engages the movable portion I86 of the element I80. This position ofmedium fire operation or engagement of the shoulder I89 with portion I86is determined by the setting of the member I9I.

I At the time the thrust member 209 moves the lower shoulder 2I0into'engagement with the plate member I92 the blade member portion I56parts the contact 7 members I58, I60 with a quick action and causes thecontact members I51, I59 to engage with a quick action to place fullprimary line voltage on the fan means I60 to increase-its speed ofoperation and consequently increase its air delivery to the fuel burner.Concurrently with the energization .of the heater I81 the heater 266which is in series circuittherewithis also energized and acts to heatthe bimetallic swltch263 in an effort to cause it to, move to opencircuit position. The length of time needed for the heater 266 to causethe switch 263 to. open is, however, so chosen relative to the length.of time necessary for movement of the thrust member 209 to its upperposition with consequent increase of voltage to the fan means I60 thatthe heater 266 will not open the switch 263 prior to the normal movementof the member 209. As soon as the increased output of the fan means I60occurs the temperature position. The switch 268 is preferably of themanual reset type and as it will not automatically return to .closedposition, manual closing is necessary and the operator is consequentlynotified of a fault in the burner apparatus.

Should the medium fire output of the burner be insuflicient to maintainthe temperature in the heated space, and the temperature falls to apro.-

determined lower temperature, the contact members 259, 252 will bebrought in engagement to energize the high fire circuit as follows:Current" fiows fromthe secondary of the transformer I46. throughlead-wire I48, terminal I68, lead wire 253, contact members 25I, 258,spring 251, element 255, contact members 259, 252, lead wire 254,terminal I 10, lead wire'262, the air controlling means 260, lead wire26I, terminal I 12, bus

bar I15, lead wire '225 heater I68, lead wire 224,

bus bar I12, terminal I66, lead wire 264, switch 263, lead wire265,'terminal I61 and through lead wire I41 back to the secondary of thetransformer I46; Energization of the high fire circuit causes the heaterI88 to heat the portion I84 thereby to gradually raise the movableportion I86 so that the spring I24 can move the valve member II1 to highfire position in engagement with the high fire adjustment screw 2 I1. Atthe same time the heater I88 is heating the portion I84 the air con-"trolling means 260 is energized. The action of the means 260 is,however, somewhat faster than the' action of the element I80 and the airsupply is increased for high fire operation more rapidly than the fuelsupply is increased.

As the space temperature increases the contact -members 252 259 willbreak the high fire circuit allowing, the heater I88 end portion I84 tocool so that the movable portion I86 moves the valve member II1 towardmedium fire position. Upon deenergization the means 260 is slower to actthan the element I80 so that the fuel supply is reduced prior to thereduction-of the air supply. As the space temperature increases'afurther predetermined amount the contact members 25I and 258 break themedium fire circuit to deenergize the heater I81 andheater 266. As theheater I61 and'portion I83 cool the movable portion I55 moves downwardgradually moving the valve member 1 toward closed position until theportion I85 engages the shoulder I89 at which time further downwardmovement of the movable portion I85 is opposed by the upward'forcesacting on the thrust member 209. Thisincreasein opposing force todownward movement of the portion I85 causes it to hesitate at theintermediate fuel flow which is determined by the setting of the collarmember 2I3 on the member 209 and the distance between the spacedshoulders 280.

The fuel flow in this hesitation position is pref-,- erablysuch that theexcess pool of fuel in the burner to be burned and/or any excess fuel inthe fuel line intermediate the outlet III and-the burner can flow to theburner and be burned,

without a smoky flame and also is such a flow that with medium fire airthe flame will not be driven down into the burner with prolongedoperation subsequent to burning at the intermediate fuel rate of flow.The total force acting upward on the member 209 is so related to thecharacteristics of the element I19 that the time interval neces sary forthe element I 19 to cause further downward movement of the valve memberI I1 after engagement with theshoulder 2I4 and downward movement of themember 209 is more than sum- 7 cient to burn the oil pool in the burnerand/or the excess oiLin the oil line leading to the burner from theoutlet ill. Subsequent to this predetermined time the movable portionI85 will move with a snap action the thrust member 209 down-- ward untilthe upper shoulder! I ll engages the top surface of the plate member t9!and also the valve member H1 downward alike amount thereby regulatingthe oil flow for pilot operation and the fan means It! for slow speedlow air delivery operation.

What is claimed and desired to be secured by Letters Patent of theUnited States is:

1. The method of regulating the ratio of fuel to air to a burner betweenpredetermined upper and lower combustion limits which includes the stepof maintaining maximum fire air supply for the upper limit whilemaintaining a reduced fuel fiow at a constant rate during a transitoryinterval while changing from the upper to the lower limit.

2. The method of controlling the supply of air and the supply of fuel toa. burner during reduction of the burner flame from a higher to a lowertime which comprises, reducing the rate of fuel supply to anintermediate rate while maintaining the rate of air supply substantiallyconstant, maintaining constant the ratio of the reduced rate of fuelflow to the air sup ly for a time interval, and then reducing the rateof air supply and further reducing the rate of fuel supply.

' 3. The method of reducing a burner flame from a high fire to a pilotfire which comprises, maintaining a substantiallyconstant air supplysuitable for the high fire,- reducing the rate of fuel supply,maintaining substantially constant the rate of flow of the reduced fuelsupply while main-' taining the constant air supply, and then reducingthe air supply and further reducing the fuel supply to provide a properfuel to air ratio for thepilot fire. V

4. The method of controlling the supply of air and the supply of fuel toa burner during reduction 'of the burner flame from a hi her to a lowerflame which comprises, reducing the rate of fuel supply to an intermedate rate while maintaining the rate of air supply substantiallyconstant,

maintaining constant the ratioof the reduced rate of fuel flow to theair supply for apredetermined assure rate, and then reducing the rate ofairsupply and further reducing the fuel supply.

'7. The method of reducing the supply of air and the supply of fuel to afuel burning apparatus having inherently a lag between the time the fuelflow is reduced by a control means and the time when reduction of thequantity of fuel in the burner pot occurs which comprises, reducing therate of fuel supply at the control means to a substantially constantlower rate while'maintaining the 'rate of air substantially constant,maintaining said reduced lower rate of fuel flow and said constant rateof air for a predetermined time interval, and then reducing the rate orair supply and further reducing the rate of fuel supply for 1 pressurewhich comprises, reducing the rate of fuel and the supply of air to afluid fuel burner fuel flow to thepool and maintaining a rate of airsupply in excess of that required for com- I bustion of .the fuel in thepool, and after the pool has been reduced to a quantity commensuratewith a reduced supply of air then supplying fuel at a further reducedrate for a further reduced pool and reducing the rate of air supply forcombustion of the reduced pool.

9. The method of reducing the supply of air and the supply of fuel toprovide a lower flame ,in a fuel burner having a fuel pool and havingmeans for supplying air to the burner under pressure which comprises,gradually reducing the rate of fuel flowto the pool and maintaining arate of air supply, in excess of that required for combustion of thefuel in the pool, and after the pool has been reduced to a quantitycommensuratewith a reduced supply of air then reducing the rate of airsupply and the rate of fuel supply substantially simultaneously and witha quick actionvto a proper fuel to air ratio for proper combustion andthe formation of a reduced pool. I I

10. The method of reducing the supply of I having high, medium and lowrates of heat outsubstantially constant time intervaL'and then.

simultaneously reducing the rate of air supply and further reducing therate of fuel supply.

5. The method of controlling the supply of air and the supply of fuel toaburner during reduction of the burner flame from a higherto alower v.flame which comprises, reducing the rate of fuel supply to anintermediate rate while maintaining an excess. rate of air supply,maintaining substantially constant the ratio of the reduced rate of fuelfiow and the excess rate of air supply for a time interval, and thenreducing the rate of air supply and. furtherreducing the rate of fuel;

supply. I

6. The method of reducing the supply of air and the supply of fuel to afuel burning apparatus having inherently a lag between the time the fuelflow is reduced by a control means and the time when reduction ofthequantity of fuel in the burner pot occurs which comprises, reducingthe rate of fuel supply to a substantially constant lower rate at thecontrol means while maintaining the rate of air'in excess of thatrequired by i said reduced lower rate of fuel, maintainingsaid reducedlower rate of fuel and said excess air until the fuel is being consumedat the reduced lower 76 having means for u l i 1 thereto under put andhaving means for supplying air to the burner under" pressure whichcomprises, reducing the rate of fuel supply from the rate of fuel supplynecessary for the high rate of heat output'to a medium rate of fuelsupply necessary for the medium rate of heat output while maintaining arate ofair supply in excess of that required for combustion of thereduced rate of fuel supply, reducing the rate of air supply to thatrate desired at said reduced rate of fuel .supply, maintaining thisdesired ratio of fuel and air as long as it is desired .to operate theburner at the medium rate of heat output, after the desired medium rateof 'heat output is no longer desired further reducing the rate of fuelsupply to a rate necessary for a heat output intermediate the medium andthe low rate of output of the burner while maintaining for apredetermined time substantially the same rate of air supply which wasrequired for the medium rate of heat output, and then substantially si--multaneously reducing the rate of air supply and further reducing therate of fuel supply for a desired fuel to air ratio for the low rate ofheat output.

11. The method of increasing the supply of fuel and the supply of air toa fluid fuel burner pressure which comprises, increasing the rate offuel fiow to an intermediate rate and increasing the rate of air flow tothe rate necessary for r a proper fuel to air ratio at a desired rate offuel flow higher than the intermediate rateof fuel fiow, maintaining theintermediate rate of fuel flow and the increased rate of air flow for [atime interval, and then increasing the rate maintaining the intermediaterate of fuel fiow and the increased rate of air flow for a timeinterval, and then gradually increasing the rate movable for controllingflow of fluid fuel, means for moving said means in one direction, meansfor limiting movement of said controlling means in said one directionthereby to position said controlling means to allow a minimumpredetermined flow of fuel to the burner for a low fire operation, meansfor moving said controlling 1 means in a second direction for increasedflow of fuel flow to the desired high rate of fuel fiow.

- 13. The method of increasing the supply of fuel and the supply of airto a fluid fuel burner having means for supplying air thereto underpressure which comprises, increasing the rate of fuel flow to anintermediate rate and increas ing the rate of air fiow to the ratenecessary for a proper fuel to air ratio at a desired high rate of fuelflow, maintaining the intermediate rate of fuel flow and the increasedrate of air flow for a time interval, then increasing the rate of fuelfiow to the desired high rate of fuel flow,

and-upon failure of the rate of air supply to increase the increasedrate after a predetermined time interval, reducing the rate of fuel flowto the original low rate.

14. In an oil burner control system, means movable in two directions forcontrolling flow of fluid fuel, means for moving said means, means forlimiting movement of said controlling means in one of said directionsthereby to allow burner for low fire operatiomsaid moving meansbeingoperable to move said controlling means in a second direction forincreasedfiow of fuel to the burner, means limiting movement of saidcontrolling means in said second direction for determining apredetermined higher flowof fuel to the burner, and means operable uponmove ment of said controlling means in one of said directions and at afuel flow intermediate to said predetermined minimum flow and saidpredetermined higher flow to cause said controlling means to hesitatefor a predetermined time in 'its movement. 1

15. In an oil burner control system, means for limiting movement of saidcontrolling means in said one direction thereby to allow a minimumpredetermined flow of fuel to the burner for low fire operation, meansfor moving said controlling means-in a second direction for increasedfiow of fuel to the burner, means lim- "iting movement of saidcontrolling means in said second direction for determining a prede offuel to the burner, means limiting movement of said controlling means insaid second direction for determining a predetermined higher flow offuel to the burner, means operable upon movement of said controllingmeans in said one direction and at a fuel flow intermediate to saidpredetermined minimum flow and said predetermined higher fiow to causesaid controlling means to hesitate at a predetermined intermediateposition for a predetermined time inits movement in said one direction,and means for moving said controlling means with a snap action from saidintermediate flow position to said minimum flow position subsequent tosaid predetermined time interval. v

17. In an oil burner control system, means movable for controlling flowof fluid fuel,means for moving said means, means for limiting movementof said controlling means in one direction thereby to allow at least aminimum predetera minimum predetermined flow of fuel to the 1controlling means being movable in a second'dimovable for controllingflow of fluid fuel, means for moving said means in one direction, means,

termined higher flow of fuel to the burner, and

means operable upon movement of said controlling means in one of saiddirections and at a fuel'fiow intermediate to said predetermined minimumfiow and said predetermined higher flow to cause said controlling meansto hesitate for a predetermined time in its movement.

16. In an oil burner control system, means mined fiow of fuel to theburner for low fire operation, said controlling means being movable in asecond direction for increased fiow of fuel to the burner, meanslimiting movement of said controlling means in said second directionfor.

determining a predetermined higher flow of fuel to the burner, meansoperable upon movement of.

said controlling means in said one direction and at a fuel flowintermediate to said predetermined minimum flow and said predeterminedhigher flow to cause said controlling means to hesitate for apredetermined time in its movement in said one direction, and means formoving said secondnamed limiting means to allow said controlling meanstobe moved further in said second direction thereby to allow apredetermined maximum flow of fuel to the burner I greater than saidpredetermined higher flow. v

18. In an oil burner control system, means movable for controllingfiow'of fluid fuel, means for moving said means, means for limitingmovementof said controlling means in one direction thereby to allowaminimum predetermined flow of fuel to the burner for low fireoperation, said rection for increased flow of fuel to the burner, meanslimiting movement of said controlling means in said seconddirection fordetermining a predetermined higher flow of fuel to the-burner,

means operable upon movement of said controlling means in said onedirection and at atfuel flow intermediate to said predeterminedminimum-flow and said predetermined higher flow to cause saidcontrolling means to hesitate in its movement in one of said directions,and means sensitive to the eifect'of the output of the burner forcontrolling said second-named moving means. D V v 19. In an oil burnercontrol system, means movable for controlling flow of fluid fuel, meansfor moving said means, means for limiting movement of said controllingmeans in one direction thereby to allow a minimum predetermined flow Iof fuel to the burner, said controlling means being movable in a seconddirection for increased flow of fuel to the burner, means limitingmove-' ment of said controlling means in said second.

direction for determining a predetermined higher flow of fuel to theburner, means for supplying air to the burner under pressure, and meansoperable upon movement of saidcontrolling means and at a fuel flowintermediate said predetermined minimum flow and said predeterminedhigher flow to cause said controlling means to hesitate for apredetermined time in its movement in said one direction.

20. In an oil burner control system, means movable for controlling flowof fluid fuel, means for moving said means, means for limiting movementof said controlling means in one direction thereby to allow a minimumpredetermlnedflow of fuel to the burner, said controlling means beingmovable in a second direction for increased flow of fuel to the burner,means limiting movement of said controlling means in said seconddirection for determining a predetermined higher flow of fuel to theburner, means for supplying' air to the burner under pressure, meanscontrolling said air supplying means, means interconnecting saidfiowcontrolling means and said second-named controlling means and operableupon movement of said flow controlling means to rection and at a fuelflow intermediate said predetermined minimum fiow and said predeterminedhigher flow to cause said controlling means to hesitate for apredetermined time in its movement in said one direction, and switchmeans responsive to the output of said air supplying means and operableto render said first-named moving means ineffective upon failure of saidair supplying means to supply air at said predetermined higher rate. V

23. In an oil burner control system, a liquid fuel burner, valve meanscontrolling the supply of fuel to said burner, spring means-urging saidvalve means toward open position, electrically heated bimetallic powermeans operatively connected to said valve means and operable to movesaid valve means toward closed position in opposition to said springmeans, electrically operated fan means supplying air to said burner,switch means, means movable by said power means for controlling saidswitch means, means exerting a force tending to move said last-namedmeans in control said air supplying means, and means said controllingmeans being movable in a second direction for increased flow of fuel tothe burner, means limiting movement -of said controlling means insaid'second direction for determining a predetermined higher flow offuel I to 'the burner, means for supplying air to the burner underpressure, means operable upon movement of said controlling means in saidone direction and at a fuel flow intermediate said predetermined minimumflow and said predetermined higher flow to cause said controlling meansto hesitate in its movement in said one direction, and switch meansresponsive tothe output of said air supplying means operable to rendersaid second-named moving means ineffective upon failure of said airsupplying means.

22; In an oil burner control system, means a movable for controlling'theflow. of fluid fuel,

- by said switch means, switch means controlling opposition to the valveclosing movement of said power means, means limiting movement of saidswitch actuating means in its opposing movement, means electricallyconnecting said switch means and said fan means for control of said fanmeans said power means, and heatactuated means positioned in heattransfer relationship with the output of said fan means andcooledthereby, said last-named means being operable upon failure of saidfan means to heat up and operate said power means.

24. In an apparatus of the character described, a first reciprocallymovable controlling member having. a shoulder, a second reciprocallymovable member having a shoulder, a first spring means urging said firstmember in one direction, a second spring means urging said second memberin said one direction, power means having an arm engageable with saidshoulders and exerting a force sufhcient to move said recipmeans formoving said means, means for limiting movement of said controlling meansin one direction thereby to allow a minimum predetermined flow of fuelto the burner for low flre operation, said controlling means beingmovable in avsecond direction for increased flow of fuel to the burner,means limiting movement of said controlling means in said seconddirection for es-' tablishing a predetermined higher flow of fuel forhigh flre operation of the burner, means for sup plying air to theburner under pressure, means limiting the output of said air supplyingmeans to that required for said low fire operation of the burner, meansfor moving said limiting means to increase the output of said airsupplying. means thereby to allow said air supplying means to supply airat a predetermined higher rate for said high fire operation, meansoperable upon'movemerit of said controlling means in said one dirocallymovable membersin a second direction against the force of said first andsaid second "spring means, means limiting movement of said reciprocallymovable members in said second direction, said power means beingoperable to exert a progressively decreasing force thereby to allow saidmovable members to move in said one direction, means limiting movementof said second movable member in said one direction, and means limitingmovement of said first movable member in said one direction, saidlast-named limiting means being so positioned relative to 'saidsecond-named limiting means that said first movable member canhavemovement subsequent to limitation of movement of said second movablemember upon sufllcient decrease in force of said power means subsequentto. limitation of movement of said second movable member.

-25. In an apparatus of the character described, a firstreciprocallymovable member having a shoulder, a second reciprocallymovable member having a shoulder, a first. spring means urging saidfirst'member in one direction, a second spring means urging said secondmember in said one direction, power means having an arm engageable withsaid shoulders and operable to move said reciprocally movable members ina second direction against the force of said first and "said secondspring means, means'limiting movement of said reciprocally movablemembers in said second direction, said power means beingoperable toexerta progressively decreasing force thereby to allow said movablemembers to move in said one direction, means limiting movement of saidsecond movable member in said one direction, and means limiting movementof said first movable member in said one direction, said last-namedlimiting means being so positioned relative to said second-namedlimiting means that said first movable member can have movementsubsequent to limitation of movement of said second movable member uponsufiicient decrease in force of said power means subsequent tolimitation of movement of said second movable member, said second springmeans being so constructed and arranged relative to said first springmeans and said power means that the sum oi. the forces exerted by saidfirst and said second spring means upon initial movement of said movablemembers in said one direction will continually exceed the opposing forceexerted by said power means prior to engagement of said second movablemember with said firstnamed limiting means so that said movable memberswill be moved in said one direction with a quick action.

26. In an apparatus of the character described, a first reciprocallymovable member having a shoulder, a second reciprocally movable member,an abutment member carried by said second movable member and having ashoulder, a first 7 spring means urging said first member in onedirection, a second spring means urging said second member in said onedirection, power means having an arm engageablewith said shoulders andoperable to extert a suficient force to move said reciprocally movablemembers in a second direction against the force of said first and saidsecond spring means, said power means being operable to exert aprogressively decreasing force thereby to allow said movable members tomove in said one direction, means for moving said abutment memberrelative to said second movable member thereby to adjust the limit ofmovement of said power means in said second direction, means limitingmovement of said second reciprocally movable member in said .first andsaid second direction, and means limiting movement of said first movablemember in said one direction, said last-named limiting means being sopositioned relative to said first-named limiting means that said firstmovable member can have movement subsequent to limitation of movement ofsaid second movable member in said one direction upon sufiicientdecrease in force of said power means.

27. In an apparatus of the character described,

a first reciprocally movable member having a shoulder, a secondreciprocally movable member having a shoulder, -a lever member having'aportion in the path of movement of said second movable member, resilientmeans operatively connected to and urging said lever member intoengagement with said second movable member and acting to urge saidsecond movable member in one direction, spring means urging said firstmember in said one direction, power means .having an arm engageable withsaid shoulders and operable to exert a sufflcient force to move saidreciprocally movable members in a second direction against the force ofsaid spring means and said resilient means, said power means beingoperable to exert a progressively decreasing force thereby to allow saidmovable members to move in said one direction, means limiting movementof said reciprocally movable members in said second direction, meanslimiting movement of said second movable member in said one direction,and means limiting movement of said last-named limiting means being sopositioned relative to said second-named limiting means that said firstmovable member can have movement subsequent tolimitation of movement ofsaid second movable member upon suificient decrease in force exerted bysaid power means.

28. In an apparatus of the character described, a casing having a firstchamber for liquid with an outlet, said casing having a second chamber,valve means movable relative to said outlet to control flow of liquidfrom said first chamber and having a portion extending into said secondchamber, said valve means having an abutment, spring means surroundingsaid valve means and interposed between said abutment and the wall ofsaid first chamber adjacent said outlet and acting to move said valvemeans in an open direction, said valve means having a shoulder withinsaid second chamber, a reciprocal member within said second chamber andhaving a shoulder, bimetallic heat actuated means secured to said casingwithin said second chamber and having an arm engageable with saidshoulders, means urging said reciprocalv member in one direction, saidbimetallic means being operable at normal temperatures to move saidvalve means toward closed position and said reciprocal member in asecond direction opposite to said one direction, electric means forheating said bimetallic means to a higher temperature than normal, saidbimetallic means when at said' higher temperature being moved by saidspring means and said urging means to allow movement of said valve meansin an open direction and said reciprocal member in said one direction,stop means limiting movement of said valve means in valve opendirection, and stop means limiting movement of said reciprocal member insaid one direction and so constructed and arranged relative to saidfirst-named stop means that said reciprocal member is limited in itsmovement in said one direction prior to limitation of movement of saidvalve means in said valve open direction.

29. In an apparatus of the character described, a casing having a firstchamber for liquid with an outlet, said casing having a second chamber,

valve means movable relative to said outlet to control fiow of liquidfrom said first chamber and having a portion extending into said secondchamber, said valve means having an abutment, spring means surroundingsaid valve means and interposed between said abutment and the wall ofsaid first chamber adjacent said outlet and acting to move said valvemeans in an open direction, said valve means having a shoulder withinsaid second chamber, a reciprocal member within said second chamber,said reciprocal member being movable between predetermined limits, an

' moved by said spring means and said urging direction andso'constructed and arranged relative to said predetermined. movement ofsaid reciprocal movement that said reciprocal member is limited in itsmovement in said onedirection prior to limitation of movement of. saidvalve means in said valve open direction.

30. In an apparatus of the character described, a first reciprocallymovable member movable in a first and a second direction, a secondreciprocally movable member movable insaid first and said seconddirections,-means engageable by and forlimiting movement of said secondmember in said first and 'said second directions, means engageable byand for limiting movement of said first member in said first direction,means urging each of said members in said first direction and intoengagement with their respective limiting means, and power meansoperable to exert a I progressivelyincreasing force thereby to move saidmembers in said second direction against the force of said urging means,said limiting means being so constructed and arranged relativc to'eachother that when said members are 818881118 their respective limitingmeans said power means must move said first member a predetermineddistance insaid second direction prior to movement of said second memberin said second direction bysaid power means.

31. In an apparatus of the character described, a first reciprocallymovable member movable in a first and a second direction, a secondreciprocreased sufiiciently to overcome the added force of said secondmember urging means.

-32. In an apparatus of the character described, a movable controllingmember having a range of movement, power means acting on said memher andholding said member at one limit of said range, means urging saidmovable member against the force of said power means, thrust meansacting against said power means and in conjunction with said urgingmeans, said urging means and said thrust means determining the reductionof force of said power means at which said urging means will move saidmovable member, and means operable within said range to limit the actionof said thrust'means against said power means so that said power meansmust have a further reduction of force prior to continuation of movementof said movable member by said urging means.

33. In an oil burner control apparatus, fuel supply means, means toregulate the rate of fuel flow from said means, means to supply airunder pressure for combustion, means to 'control saidregulating means toincrease the flow rate 'upon demand for heat, means operable upon saidincrease to render said air pressure means eflective to supply air for a-flow rate in excess of said increased rate, and means to delay furtherin-.-

' crease in the flow rate for a period subsequent so to the rendering ofsaid pressure means effective.

34. In an oil burner control apparatus, fuel supply means, means toregulate the rate of fuel fiow from said means, means to supply 'air forcombustion, means to control said regulating as means to decrease theflow rate upon cessation cally movable member movable in said first andsaid second directions, means engageable by and for limiting movement'ofsaid second member in a said first and said second direction, meansengageable by and forlimiting movement of said first member in saidfirst direction, means urging each of said members in said firstdirection and into engagement with their respective limiting means,bimetallic means operable to exert a progressively increasing force uponincrease in temperature thereby to move said members in said seconddirection against the force of said urging means, and means to heat saidbimetallic means,

said limiting means being so constructed and arranged relative to eachother that when said members are engaging their respective limitingmeans and said bimetallic means is heated, said bimetallic means mustmove said first member a predetermined distance in said second directiona prior to movement of said second member in said second direction bysaid power means thereby to cause said first member to hesitate in itsmovement in said second direction until the force exerted by saidbimetallic means has inmember.

of demand for heat, and means operable after an interval of maintainedconstant decreased fuel fiow subsequent to said decrease to decrease thequantity of air supplied by said supply means. 35. In an apparatus ofthe character described, a movable controlling member, means resistingmovement of said member and having its resist-,1

ing force decreasing during a time interval, means to move said memberin opposition to said restat ing means, means operable within the rangeoi movement of said movable member to decrease the force exerted by,said moving means to a force less than the force-exerted by saidresisting means, and means acting to hold said member against movementby said resisting means during'the period when said resisting meansforce exceeds the force exerted by said moving means,

said resisting means having its force decreasing subsequent to operationof said operable means to a force less thanthe decreased force of saidmoving means so that said moving means is operable to continue themovement of said WALTER.- s. ms. 2mm? 3. RUSSEL-

